Some 61.4% of men interviewed said women sometimes deserve to be beaten; 42.7% think that "if a woman doesn't show physical resistance when forced to have sex, it's not rape"; and 27.9% believe that sometimes women want to be raped.

Well over 40% of the men polled asserted that a man should reject his wife when she has been raped.

The findings show that sexual violence is much more than a weapon of war, activists said, and reflect widespread acceptance of patriarchal norms and rape myths. They also pointed to Congo's incendiary mix of conflict, poverty and weak law enforcement as causal factors in need of urgent redress.

The study was carried out by the South African-based Sonke Gender Justice Network and the Brazilian non-government organisationPromundo in and near Goma in Congo's North Kivu province. A total of 708 men and 754 women aged between 18 and 59 took part in individual interviews and focus group discussions in June this year.

The self-reporting of men is particularly unusual and striking. Some 34% admit having carried out some form of sexual violence in conflict, homes or other settings.

Almost two-thirds agree with the statement that "women should accept partner violence to keep the family together", and almost a third endorse the view that "a woman who is raped has provoked this by her attitude". More than a quarter believe that "a man can force a woman to have sex and she may enjoy it".

The preliminary report notes: "In qualitative interviews, men openly shared their opinions about the 'right to have sex' with their female partner even if she refuses; most men did not consider it to be rape to force their wives to have sex with them. Other men took any 'provocation' by a woman to mean that she wanted sex."

As an example, it quotes a 48-year-old man who said a girl entered his shop and asked for water: "When a girl is asking for water in such a way, she wants sex. So I took her in the middle of my shop. I think she liked it because her body accepted me to enter."

The study, part of the International Men and GenderEquality Survey, also suggests that many men are themselves victims of violence, including sexual violence, and shows a clear association between exposure to violence and increased likelihood of subsequent perpetration.

It makes recommendations including far greater promotion of gender equality in schools and public policy and a massive campaign of psycho-social care for boys and girls exposed to multiple forms of violence at young ages.

It is estimated that at least half a million women have been raped in eastern Congo since 1998, prompting the UN to brand it "the rape capital of the world".

Henny Slegh, Promundo's regional coordinator in the Great Lakes region and principal investigator for the new study, said: "The whole world knows there is a lot of sexual violence here. We want to know why. The main thing we found is there are conditions of extreme poverty and conflict and an inadequate response by the national and especially international community contributing to the cycle of violence.

"Gender inequalities exist everywhere but many parts of the world live under better conditions. In this environment it is clearly worse. There are not educational opportunities to change these attitudes. That's what responses and interventions must focus on."

But there are grounds for optimism, Slegh added, in the honesty and engagement of respondents. "Men and women said: 'This is the first time I got asked questions where I can tell my story.' One man said he'd raped a girl a week before because he felt it was normal. He was exchanging opinions and it helped him see it another way. The men were very open and said they would like groups discussions more often."

This was also welcomed by Micheline Muzaneza, a former Congolese child refugee who now works with victims at the Sonke network in Cape Town, South Africa. "Men accepting and saying, 'Yes, I did this,' is a big step," she said. "We need to work on that."

Gender inequality is handed down through the generations, she continued. "They think a woman must be in the kitchen, that a woman is like a child. The cultural attitude is that a man can beat a woman. They grew up like that, seeing their father beat their mother. To punish a rival armed movement, they say: 'Let's go and rape their women and show we are stronger than them.' The woman becomes an object."

"But I am not surprised at the outcome of this survey. It shows the ignorance of many Congolese men and that in the Congolese culture women are still today often seen as inferior to men. This attitude is also a question of education. The more men are educated, the more they respect generally women."

He added: "The armed groups consider violence as a weapon of war. And [seeing] that the system of justice is not working correctly, the impunity makes the situation even worse."

War in eastern Congo has killed and displaced millions over nearly two decades. At least half of those surveyed live below the absolute poverty line and hunger is a daily reality, with 40% of men and 43% of women having only one meal a day.

Sonke is calling for for more engagement with men and women and a transformation of gender relations and social justice. Dean Peacock, its co-founder and executive director, said: "On the question of whether men can change, the answer is certainly yes, including in Congo.

"There's also evidence that a range of interventions can speed that up: group education, mass media efforts, policy change, including the development and implementation of laws that sanction and deter violence, and disrupt the toxic combination of men's sense of entitlement to women's bodies and their sense of impunity for using violence against women.

"All of those interventions are needed desperately in Congo. There are fledgling efforts to engage men: the Congolese Men's Network, for instance, is working in Kivu to challenge men to speak out against men's violence. These must be supported and strengthened."